This application describes a training program to continue to prepare Edwin Cook, M.D. for a career as a resource person in child and adolescent psychiatry research. Dr. Cook is currently completing the second year of a 3-year clinical mental health academic award (CMHAA). Support by the CMHAA has allowed Dr. Cook to focus on supervised research training, pertinent courses, and related teaching. Specifically, Dr. Cook has completed a pilot study of the time course of effects of fenfluramine on cerebral glucose metabolism and has begun a study of the effects of fluoxetine on adults with autistic disorder in comparison to normal control adults. The purpose of these studies is to pursue evidence from preliminary studies and the work of others that dysregulation of serotonin physiology in the central nervous system may be a feature of autistic disorder and related developmental disorders. Dr. Cook has also begun to develop laboratory skills which have allowed him to begin to investigate possible signal transduction abnormalities in autistic disorder. Dr. Cook proposed to use in vitro assays of second messenger metabolism in the platelets of subjects with hyperserotonemia related to autistic disorder. If an abnormality in signal transduction is identified as a mechanism of hyperserotonemia, it will help guide investigation of identified abnormal proteins for homology to proteins important in the development of the central nervous system. Continuation of the grant will allow further development of these skills through collaboration with other investigators. Dr. Cook will continue to be mentored by his supervisor, Dr. Bennett Leventhal, and experts, Drs. Malcolm Cooper, John Metz, and Daniel X. Freedman. A particular focus will continue to be the development of the research and teaching skills necessary to serve as a resource in child and adolescent mental health research.